Table of Contents

• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Chl a/Phaeopigment concentration in water samples collected at depth from two time series stations in the Gulf of Maine (2012-2013).

Users are requested to consult with Jeffrey Runge prior to preparation of any manuscripts or reports, either written or online, that make use of zooplankton and hydrographic data originating from this study. The data are freely available without need for consultation with Dr. Runge after October, 2017.

Duplicate 100 mL, or 500-550 mL water samples were collected with Nisken bottles at the surface, 10, 20 and 40 meters. The samples were filtered under low vacuum onto Whatman GFF glass fiber filters (0.8 um) and also frequently onto 5-µm and 20-µm polycarbonate membrane filters at selected depths. The filters were placed in 5 ml of 90% acetone and cold extracted for 24 h, after which fluorescence was measured with a Turner AU-10 fluorometer.  After addition of hydrochloric acid a second fluorescence measurement was taken.  Chlorophyll and pheopigment concentrations were calculated were using equations in Strickland and Parsons (1972).

Strickland, J.D.H., and T.R. Parsons, (1972). A Practical Handbook of Seawater Analysis, second ed. Bulletin of Fisheries Research Board, 167: 201–203.

Include here are the end results of calculations (Strickland and Parsons, 1972) for Chl a and Phaeophytin concentrations in the water (mg/m³). No observations have been flagged or removed, despite some negative values under the Phaeophytin column.

"The copepod, Calanus finmarchicus, is a dominant member of the plankton in the Gulf of Maine, (GoM), despite its location at the southern edge of the species' subarctic range. Wilkinson Basin, one of the three deep basins in the GoM, harbors very high concentrations of the early developmental stages of C. finmarchicus in the summer through winter and serves as a source of C. finmarchicus to GoM coastal ledges and banks. A recent study based on C. finmarchicus habitat characteristics across the North Atlantic predicts that climate-driven change will force the distribution of C. finmarchicus northward out of the GoM over the next several decades. However, the oceanographic and life history responses of C. finmarchicus to environmental variability in the Gulf are complex and largely unknown. The research in this RAPID proposal takes advantage of a rare opportunity to test a hypothesis about the control of C. finmarchicus abundance in the GoM from climate change related external forcing. The hypothesis states that a distinctly lower C. finmarchicus abundance follows, with a two-year lag, the occurrence of a very negative North Atlantic Oscillation (NAO). The specific processes that causally connect low C. finmarchicus with the NAO are not known. The research here tests the prediction that C. finmarchicus abundance will be very low in Wilkinson Basin in 2012, two years after one of the most negative NAOs on record, dating back to the 1860?s. Field observations in the form of a time series of measurements of hydrography, food availability and C. finmarchicus stage abundance will be taken at a fixed station in Wilkinson Basin and in the Maine coastal region, supported by measurements taken on the Scotian Shelf. A research survey, coordinated with a scheduled cruise in the Gulf of Maine in September, 2012, will take additional collections in Wilkinson Basin and throughout the GoM. Frozen and ethanol preserved samples of C. finmarchicus will also be collected for population genetic studies. The abundance results will be compared with historical time series and survey data collected over the past two decades, confirming or refuting the expectation of extreme NAO influence on GoM C. finmarchicus populations." (from the Award abstract)